University Of Texas Astronomer Helps Discover Potentially Habitable Planet Orbiting Nearest Star

AUSTIN, TX -- A University of Texas astronomer helped find clear evidence of a planet -- a potentially habitable one with water -- orbiting the closest star to the sun, officials announced Wednesday.

Michael Endl was part of an international team of astronomers that found the possible planet orbiting Proxima Centauri, the closest star to the sun, university officials said. Dubbed Proxima b, the newly discovered world orbits its cool (as in relative temperature, not attitude) red parent star every 11 days.

The temperature on the star the maybe planet orbits is suitable for liquid water to exist on its surface, scientists said. The orb is a bit more massive than Earth and is the closest known exoplanet to us, university officials said, and may be the closest home for life outside our solar system to boot.

The research on this major finding will be published in in the journal Nature on Thursday, Aug.25.

Endl is convinced the found orb is a planet, he said in a prepared statement.

“We are all convinced that this is a planet, especially because there’s such a long timeline of data.” Endl said. The astronomer researched the star from 2000 to 2008 with Martin Kuerster, now of the Max Planck Institute in Heidelberg, Germany, officials said. Their data, coupled with more recent efforts, created a 16-year study of Proxima Centauri’s behavior, officials added.

In conveying the news, scientists provided some context: Proxima Centauri is a cool red dwarf star located just over four light-years from the Sun, in the constellation of Centaurus. Too faint to be seen with the unaided eye, Proxima lies near the much brighter binary star system Alpha Centauri.

For the first half of this year, telescopes around the world monitored Proxima Centauri in a coordinated effort called the Pale Red Dot campaign, university officials said. The work led by Guillem Anglada-Escudé from Queen Mary University of London focused on the near-imperceptible back-and-forth wobble of the star that is the hallmark of the gravitational pull of an orbiting planet.

To put it mildly, this discovery was a team effort. The Pale Red Dot campaign data comes from the European Southern Observatory (ESO) 3.6-meter telescope in Chile and other telescopes around the world, university officials noted. The collected data was combined with earlier study by Endl and Kuerster among others.

The upshot: At times Proxima Centauri is approaching Earth at about 3 miles per hour (5 kph) — the normal human walking pace — and at times receding at the same speed. This regular pattern repeats with a period of 11.2 days. Careful analysis of this motion indicates the presence of a planet with a mass at least 1.3 times that of the Earth, orbiting about 4.4 million miles (7 million km) from Proxima Centauri — only 5 percent of the Earth-Sun distance, university officials said.

As if the work weren't complicated enough, there was a caveat to overcome: Red dwarfs stars such as Proxima Centauri are active, can vary in ways that might mimic the presence of a planet. To exclude this possibility, scientists carefully monitored the changing brightness of the star during the campaign using the ASH2 telescope at the San Pedro de Atacama Celestial Explorations Observatory in Chile and the Las Cumbres Observatory telescope network, according to analysis.

Moreover, data taken when the star was flaring were excluded from the final analysis.

Proxima b orbits much closer to its star than Mercury does to the sun, but is is far fainter than the sun, officials noted. Consequently, Proxima b has an estimated temperature that would allow the presence of liquid surface water and it lies well within the habitable zone around the star, according to the findings.

So it might be habitable. But don't pack your bags just yet.

Despite its temperate orbit, the conditions on the surface of Proxima b may be strongly affected by the ultraviolet and X-ray flares from the star — far more intense than the Earth experiences from the sun, according to scientists.

Endl's not done with this project. He suggested that if Proxima b is found to transit across the face of its star, he's like to study it soon with the Giant Magellan Telescope, which may be able to "tease out" the composition of the planet’s atmosphere, he said.

The University of Texas at Austin is a founding partner of the collaboration building the Giant Magellan Telescope.

So, local guy helps find what could be a planet. How did you spend your summer?

>>> Images courtesy University of Texas at Austin (first image artist's impression of the planet orbiting Proxima Centauri)